package com.lse_api.utils.encryption;


import java.io.ByteArrayOutputStream;

public class Base64Encryption {

	/**
	 * 加密用	字符数组
	 */
	private static final char[] base64EncodeChars = new char[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
			'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',
			'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };

	/**
	 * 解密用	字节数组
	 */
	private static final byte[] base64DecodeChars = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
			-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55,
			56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
			21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,
			47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };

	/**
	 * Base64加密
	 * @param data
	 * @return
	 */
	public static String encode(byte[] data){
		StringBuffer sb = new StringBuffer();

		int len = data.length;
		
		int i = 0;
		
		int b1, b2, b3;

		while (i < len){
			b1 = data[i++] & 0xff;
			if (i == len){
				sb.append(base64EncodeChars[b1 >>> 2]);
				sb.append(base64EncodeChars[(b1 & 0x3) << 4]);
				sb.append("==");
				break;
			}
			b2 = data[i++] & 0xff;
			if (i == len){
				sb.append(base64EncodeChars[b1 >>> 2]);
				sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
				sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);
				sb.append("=");
				break;
			}
			b3 = data[i++] & 0xff;
			sb.append(base64EncodeChars[b1 >>> 2]);
			sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);
			sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);
			sb.append(base64EncodeChars[b3 & 0x3f]);
		}
		return sb.toString();
	}

 
	/**
	 * Base64解密
	 * @param str
	 * @return
	 */
	public static byte[] decode(String str)throws Exception{
		byte[] data = str.getBytes("ISO-8859-1");
		int len = data.length;

		ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
		
		int i = 0;
		int b1, b2, b3, b4;
		
		while (i < len){
			/* b1 */
			do{
				b1 = base64DecodeChars[data[i++]];
			}while (i < len && b1 == -1);
			if (b1 == -1){
				break;
			}
			/* b2 */
			do{
				b2 = base64DecodeChars[data[i++]];
			}while (i < len && b2 == -1);
			if (b2 == -1){
				break;
			}
			buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));
			/* b3 */
			do{
				b3 = data[i++];
				if (b3 == 61){
					return buf.toByteArray();
				}
				b3 = base64DecodeChars[b3];
			}while (i < len && b3 == -1);
			if (b3 == -1){
				break;
			}
			buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));
			/* b4 */
			do{

				b4 = data[i++];
				if (b4 == 61){
					return buf.toByteArray();
				}
				b4 = base64DecodeChars[b4];
			}while (i < len && b4 == -1);
			if (b4 == -1){
				break;
			}
			buf.write((int) (((b3 & 0x03) << 6) | b4));
		}
		return buf.toByteArray();
	}
	public static void main(String[] args){
		String testStr = "Mpm7Zfi2lCCtTYYRk6zHUzYzOGg654bKceVRjHAkBX8v76i+YaP/0TkUR7iQx9smuaCJ6lTfZS888SsdoBwDdhOKuwunlvPpnbwUoLuWsPftgDtyflvZAiwWkZWHTGLAPm6RZG3OJkcfW/bgTUewhFkA8pxjqu3cH6Sv3uquFewtgp0LlKsl3gNxB5jFwRe9ABX8FB/nr/r8gLX/6/Sh6EqnaM7La/rE3sc+j9M1q7zwPViCAzT9QnD798rgGIHiK8y4Ij+X/voB5AYF54byJQ==";
		/*String testStr1 = "5A5161C4168103A863616E3EF6CFD10A";
		String testStr2 = "81595A3D1ACBEE6F0F6DD6E5DD8D7CDE";
		String encodeStr = encode(testStr.getBytes());
		String encodeStr1 = encode(testStr1.getBytes());
		String encodeStr2 = encode(testStr2.getBytes());
		System.out.println("加密数据：" + encodeStr);
		System.out.println("加密数据1：" + encodeStr1);
		System.out.println("加密数据2：" + encodeStr2);*/

		/*byte[] decodeStr1 = decode(encodeStr1);
		byte[] decodeStr2 = decode(encodeStr2);*/
		try {
			byte[] decodeStr = decode(testStr);
			System.out.println("解密数据：" + new String(decodeStr, "ISO-8859-1"));
		}catch (Exception e){
			e.printStackTrace();
		}
	}
}
